Rescuing farmland after a flood
Flooding from a prolonged heavy rain, swollen rivers, and even levee breaches can ruin crops and create a real mess in farm fields. Farmers are left with the challenge of how to manage and revitalize their agricultural land so it’s productive again.
Ken Olson is a retired soil scientist at the University of Illinois. He says what usually happens after a flood is the field is left with an organic-clay or coat of silt on top of the soil.
"In this sediment is everything that’s in the flood water. Pathogens, sewage, all kinds of things are in it. So, when the field dries out, the sunlight usually kills the pathogens. And what does the farmer do with this thin silt coat? He will incorporate it, mix it into the topsoil after it’s dried out," says Olson.
The question is, does the worked-in sediment add a little bit of nutrients and improve productivity or is it doing the opposite? Olson says there aren’t a lot of measurements of that and each situation is different.
However, sand is another issue. Levee breeches in particular can leave thick sand deposits on the soil.
"What farmers can do if they have sand deposits is remove them. If they’re thinner than four-inches or so, there’s been some work on this, they can mix them into the topsoil," says Olson. "If they have little rills, they can plow it. But if they lose topsoil because of land scouring, that can affect their future productivity."
The best way to protect your land from the ravages of a flood is to have cover crops planted when no other crops are growing. They hold the soil in place and cut down on erosion. Cover crops also add organic matter to the soil while stimulating microbial and fungal activity.
Find more information on how to farm after the flood
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